Digital otoscope

ABSTRACT

An otoscope includes an instrument head, a tip element and an optical system. The instrument head has a distal insertion portion for insertion into an ear of a human or veterinary subject. The distal insertion portion has a distal opening. The tip element is releasably attached to the distal insertion portion. The tip element has a distal opening. The optical system is contained within the instrument head. The optical system includes a plurality of optical components. The optical system further comprises a viewing component for viewing of an image of a target of interest aligned along an optical axis disposed within said distal opening. The optical system is configured to provide a field of having a diameter equaling at least 7 mm at a distance of at least 15 mm from a distal opening of said attached tip element. The optical system is further configured to simultaneously provide a distance range of optimal focus having a range of at least 8 mm. The distance range of optimal focus includes a location at a working distance equal to about 30 mm.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation application of, and claimspriority and benefit to, co-pending U.S. patent application Ser. No.15/332,110, filed Oct. 24, 2016, entitled “Digital Otoscope”, which is acontinuation of U.S. patent application Ser. No. 13/899,803 filed May22, 2013, entitled “Digital Otoscope” and now issued U.S. Pat. No.9,474,441, which is a divisional application of U.S. patent applicationSer. No. 13/237,022 filed Sep. 20, 2011, entitled “Digital Otoscope” andnow issued U.S. Pat. No. 8,469,882, which is a divisional application ofU.S. patent application Ser. No. 11/845,512 filed Aug. 27, 2007,entitled “Digital Otoscope” and now issued U.S. Pat. No. 8,066,634,which is a continuation-in-part application of U.S. patent applicationSer. No. 10/897,590 filed Jul. 23, 2004, entitled “Otoscope” and nowissued U.S. Pat. No. 7,399,275, which claims priority based upon thefollowing provisional patent applications: U.S. Ser. No. 60/490,566,filed Jul. 28, 2003; U.S. Ser. No. 60/507,473, filed Sep. 30, 2003; andU.S. Ser. No. 60/543,858, filed Feb. 11, 2004. All of the aforementionedpatent(s) and patent application(s) are herein incorporated by referencein their entirety.

FIELD OF THE INVENTION

This invention relates generally to an otoscope that incorporates animage forming device, such as a digital camera, and in particular to anotoscope further providing optical characteristics that enhance medicalinspection of both human and veterinary subjects.

BACKGROUND OF THE INVENTION

An otoscope is used for inspection of an ear canal or a nasal cavity.Typically, a prior art otoscope includes one or more lenses providing afixed magnification of light received, without providing a separatemechanism for adjusting focus over any significant range, if over anyrange at all. Whether a particular target within the ear canal, such asthe tympanic membrane (ear drum), is at or near optimal focus withrespect to the observing eye of a medical practitioner, generallydepends upon the location of the otoscope with respect to the target.

SUMMARY OF THE INVENTION

In one aspect, the invention provides for a digital otoscope for forming(imaging) live and still digital images of anatomical details of a bodyof a human or veterinary subject, and having associated opticalcharacteristics that improve the quality of visual information gatheredfor medical inspection of both human and veterinary subjects.

The digital otoscope is configured to attach to a tip element havingdimensions that are small enough to fit into a small body cavity, suchas an ear canal, nasal cavity or throat cavity, for example. An attachedtip element can be selected from a plurality of different tip elementsthat are each configured to attach to the otoscope 1000. An attached tipelement and the otoscope 1000 enclose an assembly of optical componentsyielding optical characteristics that provide a substantially wide fieldof view and a substantially wide range of optimal focus from which toform visual information within a small and confined ear, nasal or throatcavity, for example.

In some embodiments, the tip element is configured to be inserted atleast 15 mm into a representative human ear canal, and configured toprovide optical characteristics that include a field of view of at least7 mm at a distance of less than 10 mm from a distal end of the tipelement, and a distance range of optimal focus starting at less than 5mm from a distal end of the tip element and extending greater than 20 mmfrom a distal end of the tip element.

The foregoing as well as other objects, aspects, features, andadvantages of the invention will become more apparent from the followingdescription and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and features of the invention can be better understood withreference to the claims and drawings described below. The drawings arenot necessarily to scale, the emphasis is instead generally being placedupon illustrating the principles of the invention. Within the drawings,like reference numbers are used to indicate like parts throughout thevarious views. Differences between like parts may cause those parts tobe indicated by different reference numbers. Unlike parts are indicatedby different reference numbers.

FIG. 1 illustrates a top perspective view of an embodiment of a digitalotoscope that incorporates a digital image forming device and that is incommunication with a computing device via a communications channel.

FIG. 2 illustrates a side cross-sectional view of the embodiment of thedigital otoscope.

FIG. 3 illustrates an exploded view of internal components of theembodiment of the digital otoscope.

FIG. 4 illustrates a side cross-sectional view of the lens train of thedigital otoscope.

FIG. 5 is a diagram representing the field of view and the entrancepupil in relation to the most distal lens located within the tip elementof the digital otoscope.

FIG. 6A is a diagram representing a distance range of optimal focusprovided by the human configuration of the digital otoscope.

FIG. 6B is a diagram representing a distance range of optimal focusprovided by the veterinary configuration of the digital otoscope.

FIG. 7A is an illustration of a typical human ear canal.

FIG. 7B illustrates a representative human ear canal.

FIG. 8 illustrates placement of the tip element within therepresentative human ear canal.

FIG. 9 illustrates an image of a tympanic membrane formed from thedigital otoscope 1000 at or near optimal focus.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a top perspective view of an embodiment of a digitalotoscope 1000 that incorporates a digital image forming device (SeeFIGS. 2-3) and that is in communication with a computing device 1090 viaa first communications channel 1050. In this embodiment, the imageforming device is implemented as a digital camera and the communicationschannel 1050 is implemented as a wireline (cable connection) type ofcommunications channel 1050 and the computing device 1090 is implementedas a personal computer 1090.

In this embodiment, the digital camera is embedded into the housing ofthe digital otoscope 1000 (See FIGS. 2-3). The digital camera isconfigured to form image information that represents a still or a liveimage. In this embodiment, the digital camera is implemented as a Micron⅓ Inch SOC Megapixel CMOS Digital Image Sensor, also referred to hereinas the image sensor or imager. In other embodiments, other models ofdigital cameras from the same or different suppliers, are employed tofunction as the image forming device.

As shown, the otoscope 1000 includes an instrument head 18 including asurrounding housing 1020 and a distal insertion portion 29 that isinsertable into an ear canal. An optical axis 27 is defined as beingnearly (proximately) centric to a field of view of the imager. A focusposition visual indicator 209 is located along a surface 202, alsoreferred to as a recessed surface 202, that is recessed with respect tothe surface of the housing 1020. The recessed surface 202 is a gripableelastomeric cover 202 that is configured so that a user of the otoscope1000 can press against and push it in a direction that is tangential toits surface 202, to rotate it around the optical axis 27.

The imager forms live (moving) or still images using an array of1280×1024 pixels having an aspect ratio of (5:4). While operating in alive mode, the imager streams (communicates over time) live images whileemploying an interspersed 640×512 subset (one quarter)) of the array ofpixels, herein referred to as currently active pixels. The remaininginterspersed pixels are blanked and herein referred to as currentlyinactive pixels. While operating in live mode, upon capturing a stillimage, the imager instead employs all 1280×1024 pixels to represent theformed still image, utilizing all pixels as currently active pixels.

In this embodiment, live images are streamed (communicated) in real timewithout any significant portion of the live image being first storedwithin the otoscope 1000. In other embodiments, at least a significantportion of a live image is stored within the otoscope 1000 before and ifany communication of the live image is performed.

Typically, the formed image information represents a view of tissuewithin a portion of a body cavity such as an ear canal or nasal cavity.While being formed, the object of interest is located within a field ofview of the otoscope 1000 (See FIG. 5). The diameter (linear extent) ofthe field of view is determined by optical characteristics of theotoscope 1000. The field of view can be altered via a zoom magnificationmode. When the zoom magnification mode is on, a center portion (subset)of the default field of view is magnified and represented by thecurrently active pixels. The default field of view is active when thezoom magnification mode is off.

While operating with zoom magnification mode off, an entire field ofview is represented by the currently active pixels. While operating withzoom magnification mode on, a central portion (approximately one-half ofthe diameter) of the entire field of view is represented by thecurrently active pixels.

A proximal end of the otoscope 1000 includes to two elastomeric pushbuttons 1002 a-1002 b, also referred to as elastomeric switches 1002a-1002 b. Two buttons 1002 a-1002 b are provided to accommodate bothright and left handed users of the otoscope 1000. A pressing of eitherpush button (switch) 1002 a-1002 b causes the imager to form an image,or to toggle a zoom magnification mode of the imager, or to rotate theimage currently being formed by 180 degrees.

When either elastomeric push button 1002 a-1002 b is pressed andreleased within a span of time that is less than two seconds, the imagerforms an image. When either elastomeric button 1002 a-1002 b is pressedand released in a span of time that is greater than 2 seconds, theimager toggles its zoom magnification mode (off is the (default)). Whenboth elestomeric buttons 1002 a-1002 b are pressed and released in aspan of time that is greater than 4 seconds, the imager rotates an imagecurrently being formed by 180 degrees.

While in use, the otoscope 1000 is designed to be held (oriented) in anupright position (as shown), referred to as a hammer position, or heldin an upside down position (not shown), referred to as a pencilposition. In other embodiments, the otoscope 1000 includes anaccelerometer (not shown) which detects the orientation of the otoscope1000 in order to reverse the image rotation by 180 degrees, when theotoscope orientation is reversed by 180 degrees.

In this embodiment, the communications channel 1050 is implemented as auniversal serial bus (USB) version 2.0. A USB cable connector 1004 isdisposed at the rear end of the otoscope 1000. A USB cable 1050,constituting the first communications channel 1050, is attached to aproximal (rear) end of the digital otoscope 1000 via the USB cableconnector 1004. The image information formed by the image formingdevice, namely the imager, is communicated via the communicationschannel 1050 from the imager to the personal computer 1090, alsoreferred to as a computer 1090. In other embodiments, the imageinformation is stored into memory within the otoscope 1000 before beingcommunicated via the communications channel 1050.

In other embodiments, the otoscope 1000 is configured to provide memoryto store digital information, such as including image information. Thememory is implemented as volatile random access memory (RAM) ornon-volatile flash memory. In some embodiments, the memory is configuredto be separable and portable from the otoscope 1000. In someembodiments, the portable memory is implemented a portable universalserial bus (USB 2.0) compatible memory, such as a portable memory thatis configured to interoperate with digital cameras, or as portablememory within a thumb drive, provided by suppliers including theScandisk Corporation.

The computer 1090 is located a distance away from the otoscope 1000.Typically, the distance away at which the computer 1090 is located iswithin the vicinity of the otoscope 1000, such as within the same roomor same office space that the otoscope 1000 is being used. In otherembodiments, the computer is located farther from the otoscope 1000.

The first communications channel 1050 enables the digital otoscope 1000to communicate the image information formed by the imager to thecomputer 1090 for visual display, and/or for processing, and/or forstorage and/or for further communication to another computing device(not shown) via a second communications channel (not shown).

The computer 1090 can be implemented from one of a variety of computingplatforms. Preferably, each computing platform executes operating systemsoftware 1090 c including one or more device drivers for interfacingwith devices associated with the computer 1090.

In this embodiment, the computer 1090 executes the Microsoft Windows XPoperating system software 1090 c and the otoscope 1000 is configured tointeroperate with the Windows XP device drivers as a Windows OperatingSystem standard video device. Interoperation is bi-directional so thatat least command and configuration information can be communicated fromthe computer 1090 to otoscope 1000 and image information can becommunicated from the otoscope 1000 to the computer 1090.

This embodiment enables the otoscope 1000 to interoperate with theWindows XP operating system software as a plug and play device andfurther enables a user to utilize a variety of software, including theWindows XP Explorer browser program and other Microsoft Windows basedvideo processing application software, to display and process imageinformation.

Optionally, other operating systems and other browser programs and canbe installed and executed by the computer 1090. Preferably, theoperating system is compatible with the USB 2.0 standard. For example,the Vista operating system supplied by Microsoft, the Linux operatingsystem, versions of which are supplied from Red Hat and other suppliers,and the Apple Macintosh operating system can be installed and executedon the computer 1090. Other browsers, for example, that are compatiblewith particular operating systems, such as the Mozilla Firefox or theApple Safari browsers and can be installed and executed on the computer1090 where compatible.

The otoscope 1000 includes permanently stored digital logic, alsoreferred to as firmware (not shown), executed by a processor (not shown)that is embedded within the otoscope 1000. The firmware is configured toenable streaming video from the otoscope 1000 to the computer 1090 anddownloading of software from the computer 1090 to the otoscope 1000 viathe communications channel 1050.

Software that is downloaded to the otoscope 1000 can alter or add to thefunctionality of the otoscope 1000. For example, downloaded software canrecalibrate and/or re-program the operation of the otoscope 1000.Software, referred to as (otoscope resident) computer interfacesoftware, can function to interoperate with the host computer and (hostresident) computer interface software, to enhance the interoperationbetween the otoscope 1000 and the host computer 1090.

In some embodiments, a host device driver and/or other software,referred to as (host resident) computer interface software, is suppliedfor installation onto the computer 1090 and interoperation with thedigital otoscope 1000. The host device driver and other software can beinstalled via the Internet or via portable media such as for example, acompact disc or a USB port compatible memory.

For embodiments involving the Microsoft Windows operating system, thehost device driver is configured to be compliant with the MicrosoftWindows Driver Model Connection Streaming Architecture (WDM-CSA). Insome embodiments, the other software is supplied to providefunctionality to perform still image processing, device calibration, orto conform to other manufacturing requirements etc. For example, in someembodiments, the supplied software can function to trigger otoscopeimage forming and capture from the host computer 1090.

Alternatively, the first communications channel 1050 can be implementedas another type of wireline communications channel, such as complyingwith the IEEE 1394 standard, a version of which is known as Firewire.Or, the first communications channel 1050 can be implemented as awireless communications link, such as complying with wirelesscommunications standards including the IEEE 802.11 or IEEE 802.15. Aversion of the IEEE 802.15 standard is known as the Bluetooth wirelesscommunication standard.

The topology of the first communications link can be a point to pointcommunications link, or as a local or wide area network communicationslink. Like the first communication channel 1050, the secondcommunications channel can be implemented as a wireline or wireless typeof communications link and further as point to point, or as a local orwide area network type of communications link.

In some embodiments, the computing device can be implemented as acomputing device that is smaller and more portable than a personalcomputer, such as a personal digital assistant (PDA). Some PDA's areconfigured to execute Windows XP and can interoperate (transmit commandand configuration information to and receive image information from) theotoscope 1000, as a Windows plug and play device.

In some embodiments, the computing device is configured to execute nonMicrosoft operating systems. For example, computers supplied by AppleComputer employ a NuBus architecture and also provide plug and playfunctionality. In this embodiment, the otoscope 1000 and its firmwareare configured to interoperate with plug and play functionality ofoperating systems supplied by Apple Computer.

In some embodiments, image information can be transferred to a smallerdevice, such as an Apple IPod computing device. For example, in some usescenarios, image information is transferred from the personal computer1090 to an IPod device (not shown) via the second communicationschannel.

FIG. 2 illustrates a side cross-sectional view of the embodiment of thedigital otoscope 1000 of FIG. 1. The structure of the digital otoscope1000 is mostly the same as the structure described for the non-digitalotoscope (associated with a figure reference number 10) that isdescribed within the parent patent application Ser. No. 10/897,590,herein also referred to as the '590 patent application, which isincorporated herein by reference.

Like the non-digital otoscope (10) described within the '590 patentapplication, the structure of the digital otoscope 1000 includes aninstrument head 18, a (conical) tip element 40 having a distal end 44, atip element retainer member 240, a distal axisymmetrical insertionportion 29 having a distal opening 29 a, rotatable actuator knob 252, aninner former assembly 116, cylindrical sleeve member 144, illuminationassembly 124, lamp retainer 140, and 128 miniature incandescent lamp,for example.

Further, the otoscope 1000 includes the same illumination and pneumaticsystem design, the same tip element attachment and removal mechanism andmuch of the same optical system design as described within the '590patent application. The otoscope 1000 has much of the same focusmechanism as that of the '590 patent application. For example, thehousings, focus wheel, compression spring and ball of the otoscope 1000are the same as the non-digital otoscope (10) and provide the samedetent related functionality and feel as provided by the non-digitalotoscope (10).

Unlike the non-digital otoscope (10) described within the '590 patentapplication, the structure of the digital otoscope 1000 includes alongits optical axis 27, components that are not included among thecomponents of the '590 patent application, in order to interoperate withthe image forming device 1020, which is not included within the '590non-digital otoscope. For example, the digital otoscope 1000 includes anew lens doublet 1406 and 1408 (See FIG. 4) that is not included withinthe lens train of the '590 patent application.

Also, unlike the non-digital otoscope 1000 described within the '590patent, the digital otoscope 1000 excludes the components of the '590lens train, except for the lens doublet 96, 100. The non-digitalotoscope 1000 excludes a first relay lens (104), a second relay lens(112), and lenses (190, 194) of the eyepiece mechanism, for example.Further, the digital otoscope 1000 excludes lens retainer member (176)and a ball 204, for example.

Within the non-digital otoscope (10), the focus adjustment mechanism(focus wheel) moves one or more lenses in an axial direction to adjustfocus. Within the digital otoscope 1000, the focus adjustment mechanism(focus wheel) instead moves the imager, and not a lens, in an axialdirection to adjust focus.

In some embodiments, the digital otoscope 1000 includes an audio inputdevice, such as a microphone (not shown), that is configured to inputaudio information for storage and communication in association with theimage information of the image forming device. The audio information canprovide a timely explanation of the image information as it is formed,in order to enhance digital documentation of a medical inspectionprocedure.

In some embodiments, the otoscope 1000 includes a view finder to enablethe user of the otoscope 1000 to view an image through the view finderof the otoscope at the moment of capturing an image. The view finder canbe implemented as one or more eye piece lenses or as a liquid crystaldisplay (LCD) attached to or included within the otoscope 1000.

To accommodate the view finder, the optical axis 27 can be folded,meaning that the optical axis 27 is split and a copy of the image isredirected to the view finder. In some embodiments, a single lens reflex(SLR) mirror or a beam splitter component is employed to direct theimage to the image forming device and the view finder.

FIG. 3 illustrates an exploded view of a set of components residingalong the optical axis 27 of the digital otoscope 1000. These componentsare located internal to the otoscope 1000 and are designed to enableinteroperation of the imager 1202 with other components of the otoscope1000.

As shown, the set of components includes an innerformer and coneassembly including an optics tube assembly 1310, a housing 1312, a userfocus adjustment 1314, a spring 1316, an imager holder 1318, an infrared(IR) filter 1320, a face seal (dust seal for the imager) 1322, an imager1202, an imager circuit board 1326, a USB board 1328, an imager adjusternut 1330, a connector board 1332, an elastomeric switch 1334 and a bezel1336.

When the otoscope 1000 is fully assembled, the user focus adjustment1314 rotates synchronously with the focus position visual indicator 209.This mechanism enables the user of the digital otoscope 1000 to performfocus adjustment and to achieve optimal focus at a particular locationthat is selected by a user of the otoscope 1000.

FIG. 4 illustrates a side cross-sectional view of the lens train of thedigital otoscope 1000. Like the non-digital otoscope (10) describedwithin the parent '590 patent application, the lens train 1400 of thedigital otoscope 1000 includes a lens doublet 96, 100 and a lens tube1402, an o-ring 1412 and a retainer 1414 which is the same as that ofthe non-digital otoscope (10) described within the parent '590 patentapplication.

Unlike the non-digital otoscope (10) described within the parent '590patent application, the lens train 1400 includes a new spacer 1404, anew lens doublet 1406 and 1408, a new aperture 1410, and a new imagerplane 1416. The imager plane 1416 and a plane of optimal focus arelocated at the same location.

Unlike the non-digital otoscope (10) described within the '590 patentapplication, the lens train 1400 does not include a first relay lens(104) and a second relay lens (112) and lenses 190, 194 of thenon-digital otoscope described within the '590 patent application. Thelenses 190,194 move within the non-digital otoscope in response to focusadjustment.

FIG. 5 illustrates a side cross-sectional view of the tip element 40along the optical axis 27 of the otoscope 1000. As shown from this view,the distal lens 96 and a distal entrance pupil 1420 are located insideof the tip element 40. The most distal end 44 of the tip element 40includes an opening 44 b surrounded by a wall. The most distal end 44with its opening 44 b, functions as an aperture that limits light raysentering the tip element 40. The opening 44 b is circular in shape (notshown from this perspective) and is substantially perpendicular to theoptical axis 27. Furthermore, the opening 44 b is oriented substantiallyparallel to and accordingly, is also referred to as facing the field ofview 1510.

The opening 44 b has a diameter typically equal to about 4.24 mm, alsoreferred to as an inner diameter of the most distal end of the tipelement 40. The wall of the tip that surrounds the most distal end ofthe tip element has a width equal to about 0.38 mm. Hence, the outerdiameter of the most distal end of the tip element 40 is equal to about5.0 mm.

The field of view 1510 is perpendicular to the optical axis 27 at alocation within a volume of space that can be viewed by the imager 1202of the otoscope 1000. In accordance with the orientation and shape ofthe opening 44 b, the field of view 1510 has a circular shape (not shownfrom this perspective). The field of view increases with increasingdistance away from the opening 44 b.

An object within the field of view 1510 is viewable by the imager 1202and is represented by a set of pixels within the imager 1202. The numberof pixels representing an object within the field of view is referred toas the resolution of the object within the imager 1202. The resolutionof an object within the field of view 1510 decreases as a function ofthe distance of the object from the imager 1202.

The magnification of an object is a ratio of the size of an image of theobject, and the actual size of the object. Like the resolution of anobject, the magnification of an object within the field of view 1510decreases with increasing distance of the object from the imager 1202.

A working distance 1530 is defined as a distance between a locationwithin the field of view 1510 and the distal most lens 96 of theotoscope 1000. The lens inset distance 1532, is defined as a distancebetween the most distal end 44 a of the tip element 40 and the distallens 96, and is equal to approximately 17.6 mm for this embodiment. Thetip offset distance 1534 is equal to a distance between the most distalend 44 a of the tip element 40 and a particular object within the fieldof view 1510, such as the tympanic membrane (not shown).

The optical characteristics of the otoscope 1000 enable forming of lightreceived through the distal opening 44 a of the tip element 40 withoutcausing vignetting, which is the occlusion of light from different areasof the field of view. As shown, rays of light passing through the distalopening of the tip element 40 form the distal entrance pupil 1420. Therays of light exiting the distal entrance pupil 1420 expand towards thedistal lens 96, but the distal lens 96 is sufficiently wide andproximate to the distal entrance pupil 1420 to intercept substantiallyall of the rays of light exiting the distal entrance pupil 1420.

The field of view 1510 increases in size as a function of the distancebetween an object within the field of view and the otoscope 1000. Inthis embodiment, for example, at the opening 44 b of the distal end ofthe tip element 40, a location having a tip offset distance equaling 0.0mm and a working distance of 17.6 mm, (pupil offset distance 14.54), thefield of view 1510 has a diameter of about 4.24 mm. The size of thefield of view 1510 equals the size of the opening 44 b.

At a tip offset distance equal to 9.4 mm and a working distance of 27mm, (pupil offset distance 23.94), the field of view 1510 has a diameterof about 7.0 mm. At a tip offset distance equal to 20.4 mm and a workingdistance of 38 mm (pupil offset equal to 34.94 mm), the field of view1510 has a diameter of about 9.85 mm.

FIG. 6A is a diagram illustrating the optical characteristics of thehuman configuration of the otoscope 1000 with respect to a distancerange of optimal focus. A distance range of optimal focus is a range ofdistance from the otoscope 1000 within which the otoscope 1000 canprovide optimal focus adjustment.

By default, for the human configuration, the zoom magnification featureof the imager 1202 is off. When the imager zoom feature is off, theotoscope 1000 provides optimal focus for a field of view located withina range of working distances between 22 mm and 38 mm, which are equal totip offset distances of 4.6 mm and 20.4 mm respectively. At optimalfocus, the resolution is equal to about 16 line pairs per millimeter.When the zoom magnification mode of otoscope 1000 is on, the resolutionis equal to about 28 line pairs per millimeter at optimal focus.

An object can be viewed with acceptable focus within a range of workingdistances between 20 and 44 mm, which are equal to tip offset distancesof 2.6 mm and 26.4 mm respectively. At acceptable focus, the resolutionis equal to about 10 line pairs per millimeter.

As a result, the nearest distance of an object from the distal end ofthe tip 40 that can be viewed or imaged with the optimal focus is 4.6mm. The farthest distance of an object from the distal end of the tip 40that can be viewed or imaged with the optimal focus is 20.4 mm. Theabove described optical characteristics yield benefits when employedwithin a small and confined body cavity, such as a human ear canal.

FIG. 6B is a diagram illustrating the optical characteristics of theveterinary configuration of the otoscope 1000 with respect to a distancerange of optimal focus. By default, for the veterinary configuration,the zoom feature of the imager 1202 is on. In some veterinaryembodiments, the zoom feature cannot be turned off.

When the imager zoom feature is on, the otoscope 1000 provides optimalfocus for a field of view located within a range of working distancesbetween 30 mm and 100 mm, equal to tip offset distances of 12.4 mm and82.4 mm respectively. The expanded distance range of optimal focusaccommodates much larger ear canals possessed by some animals, such asdogs and cats for example.

As a result, the nearest distance of an object from the distal end ofthe tip 40 that can be viewed or imaged with the optimal focus is 12.4mm. The farthest distance of an object from the distal end of the tip 40that can be viewed or imaged with the optimal focus is 82.4 mm. Theseoptical characteristics are useful when employed within a small andconfined cavity, such as a an ear canal of a veterinary subject.

FIG. 7A is an illustration of a typical human ear canal 500. As shown,the ear canal includes an opening 510 and a tympanic membrane (ear drum)530 located within it. A perspective of the tympanic membrane (ear drum)530 as seen from the opening 510 of the ear canal 500, has a largeprofile, referred to herein as its visible profile. The visible profileof the ear drum 530 shows substantially one side of the ear drum,referred to as the visible side of the ear drum. The visible side of theear drum 530 is somewhat circular in overall shape and has an averagediameter width of about 7 mm. Also, the visible side has a center point532 along a surface that faces somewhat downward and away relative tothe opening of the ear canal, and is referred to as being tilted.

A distance between the opening 510 of the ear canal and the center point532 of the visible profile of the tympanic membrane is 20 mm. Eachcross-section of the ear canal 500, that faces and is visible from theperspective of the opening 510, is also some what circular. Because eachcross-section of the ear canal it is not exactly circular, eachcross-section does not have a uniform (constant) width (diameter) as acircular cross-section would have. To address this circumstance, thewidth of each cross-section of the ear canal will be defined as thedistance from its upper most surface to its lower most surface, which isdiscernable from the perspective of this figure.

Accordingly, as illustrated, the width of the cross-section of ear canalat its opening is approximately 8 mm. Moving from the opening 510towards the ear drum 530, the cross-section of the ear canal narrows. Ata location 512 of about 16 mm from the opening 510, the cross-section ofthe ear canal narrows to approximately 5 mm. Moving further towards theear drum 530, the cross-section of the ear canal widens to in excess of5 mm at the ear drum 530.

Actual dimensions of each human ear canal vary across the entire humanpopulation and a compilation of which forms a statistical distribution.It is understood that the typical ear canal 500 is located at orsubstantially proximate to the center, also referred to as the mean ormedian, of the aforementioned statistical distribution.

FIG. 7B illustrates a representative human 550 ear canal that representsand approximates the typical human ear canal of FIG. 5A. Therepresentative ear canal 550 is a useful model that illustrates theoperation of the otoscope 1000 within an environment that it is designedto work within.

The representative ear canal 550 has an upper surface that is horizontal(level) and a lower surface is not parallel to its upper surface andthat rises gradually towards the ear drum 580, and has a cross-sectionbetween its opening 560 and its ear drum 580 is circular in shape. Thediameter width of the cross-section of the representative ear canal 550varies linearly between its opening 560 and the ear drum 580. At alocation of its opening 560, the diameter of the representative earcanal 550, also referred to as its width or diameter width, is equal to8 mm. At a location 562 that is located 16 mm inside of the opening ofthe representative ear canal 550, the diameter width of itscross-section is equal to 5 mm.

The diameter width of the cross-section of the representative ear canal550 varies and narrows linearly between location 560 and location 562.The diameter width of the cross-section of the representative ear canal550 widens linearly between location 562 and location 564 which islocated at about the center point 582 of the visible profile of the eardrum. The location 564 is located 20 mm inside of the opening 560 of therepresentative ear canal 550.

FIG. 8 illustrates placement of the tip element 40 within therepresentative human ear canal 550. As shown, the tip element 40 isplaced about midway into the ear canal 550. The distal end of the tipelement 40 is located 10 mm inside of the ear canal 550 from its opening560.

At this location, the ear drum 580 is well within the distance range ofoptimal focus provided by the otoscope 1000 in its human configuration(See FIG. 6A). The range of optimal focus starts a location 810 that is4.4 mm from the distal opening 44 b (4.6 mm before the ear drum) andends 20.4 mm from the distal opening 44 b, extending 812 well beyond themost distant portion of the ear drum 580 and tissue surrounding the eardrum 580.

In this location, the field of view at the location of the center pointof the visible profile of the ear drum 580 has a diameter of 7 mm, whichis more that sufficient to encompass the entire eardrum 580 within theformed still or live image. Using focus position visual indicator 209,still or live image information is obtained via the otoscope 1000 withoptimal focus and maximum visual acuity.

There may be circumstances where it is difficult to insert the tipelement 40 into the ear canal 550. For example, an ear canal may beinfected and/or be cluttered with cerumen (ear wax). In thesecircumstances, the distance range of optimal focus continues to enableimage information to be formed with optimal.

For example, if distal opening 44 b of the tip element 40 can only beinserted 5 mm into the ear canal 550, the ear drum 580 is located 15 mmfrom the distal opening 44 b and remains well within the distance rangeof optimal focus. The field of view 1510 at this location exceeds adiameter of 7 mm. Using focus position visual indicator 209, still orlive image information of the entire eardrum 580 and its anatomicaldetails (surrounding tissue) is formed via the otoscope 1000 withoptimal.

Even if the distal opening 44 b of the tip element 40 cannot be insertedinto the ear canal 550 and is constrained to be located at the opening560 of the ear canal 550, the ear drum 580 within the distance range ofoptimal focus. In this circumstance, the ear drum is located 20 mm fromthe distal opening 44 b while the range of optimal focus extends to adistance of 20.4 mm from the distal opening. Beyond 20.4 mm, the focusis near optimal and acceptable within an additional 6 mm (See FIG. 6A).

Optionally, in this circumstance, the zoom magnification mode can be seton. As a result, the ear drum and surrounding tissue are entirely withinthe range of optimal focus (See FIG. 6B) and the magnification isdoubled to reveal finer detail to the imager and the user.

FIG. 9 illustrates an image of a tympanic membrane formed from thedigital otoscope 1000 at or near optimal focus. As shown, small detailsof the entire tympanic membrane including fine blood vessels are visiblefrom the otoscope 1000. These small details are visible at a location inexcess of 10 mm from the distal opening 44 a of the tip element 40.

The following summarizes some of aspects of the invention. In someembodiments, the invention provides for an otoscope including aninstrument head having a distal insertion portion for insertion into anear, the distal insertion portion having a distal opening, anaxisymmetric tip element releasably attached to the distal insertionportion, the tip element having a distal opening; and an optical systemcontained within the instrument head, the optical system including aplurality of optical components and an aperture stop about which theoptical components are disposed, the optical system forming an entrancepupil distal to the distal opening of the distal insertion portion butproximal to the distal opening of the attached tip element, the opticalsystem further including an image forming device that is configured toform image information that represents a still or a live image of atarget of interest aligned along an optical axis with the distalopening, the optical system being capable of capturing substantially theentire tympanic membrane of a patient at one instant in time.

In some embodiments, the invention provides an otoscope including aninstrument head having a distal insertion portion for insertion into anear of a human or veterinary subject, the distal insertion portionhaving a distal opening, an tip element releasably attached to thedistal insertion portion, the tip element having a distal opening; andan optical system contained within the instrument head, the opticalsystem including a plurality of optical components; and where theoptical system further includes a viewing component for viewing of animage of a target of interest aligned along an optical axis disposedwithin the distal opening, and the optical system being configured toprovide a field of having a diameter equaling at least 7 mm at adistance of at least 15 mm from a distal opening of the attached tipelement; and the optical system being further configured tosimultaneously provide a distance range of optimal focus having a rangeof at least 8 mm, the distance range of optimal focus including alocation at at a working distance equal to about 30 mm.

Optionally, the otoscope is configured so that the distal opening of theattached tip element can be inserted into a representative human ear towithin at least 10 mm of a tympanic membrane. Optionally, the opticalsystem being further configured to simultaneously provide a range ofmagnification of an object within the field of view within a range ofbetween about 0.4 and about 0.6.

In some embodiments, the optical system includes an entrance pupilhaving a diameter that is less than 5 mm and that is located outside ofthe instrument head and within the attached tip element. Optionally, theviewing component is an eyepiece including at least one optical element.Optionally, the otoscope includes a focusing mechanism that is useraccessible and that moves a lens along the optical axis. Optionally, theviewing component is an image forming device that is configured to formimage information and where the device has a zoom magnification feature.

In some embodiments, the otoscope includes a focusing mechanism that isuser accessible and that moves the image forming device along theoptical axis. Optionally, the otoscope provides a field of view equal toat least 7 mm at a working distance of less than or equal to 35 mm.

In other embodiments, the otoscope includes a digital image formingdevice having a zoom magnification feature, an instrument head having adistal insertion portion for insertion into an ear of a human orveterinary subject, the distal insertion portion having a distalopening, an tip element having a distal opening; and an optical systemcontained within the instrument head, the optical system including aplurality of optical components; and where the optical system having atip element configured to penetrate at least 5 mm into a representativeear canal and providing an distance range of optimal focus having alength of at least 5 mm.

In other embodiments, the invention provides an otoscope including aninstrument head having a distal insertion portion for insertion into anear of a human or veterinary subject, the distal insertion portionhaving a distal opening, a tip element having a distal opening; and anoptical system contained within the instrument head, the optical systemincluding a plurality of optical components; and where the tip elementconfigured to receive penetrate a representative ear canal by at least 5mm and receiving a field of view having a diameter of at least 7 mm at aworking distance equal to less than or equal to 50 mm from the distalopening.

Optionally, the field of view is received at a working distance of lessthan or equal to 40 mm. Optionally, the field of view is received at aworking distance of less than or equal to 30 mm.

In some embodiments, a distance range of optimal focus has a length ofgreater than or equal to 5 mm. Optionally, a distance range of optimalfocus has a length of greater than or equal to 10 mm and includeslocation at a working distance equal to 32 mm.

In some embodiments, the otoscope has a zoom feature. Optionally, thezoom feature enables a distance range of optimal focus having a lengthof at least 35 mm. Optionally, the distance range of optimal focusincludes a location of a working distance equal to 65 mm.

In some embodiments, the otoscope is configurable where the field ofview is received at a working distance of less than or equal to 60 mm.

While the present invention has been explained with reference to thestructure disclosed herein, it is not confined to the details set forthand this invention is intended to cover any modifications and changes asmay come within the scope and spirit of the following claims.

What is claimed is:
 1. A digital medical diagnostic instrumentcomprising: an instrument head including a distal insertion portion at adistal end and a proximal end; an optical system disposed within theinstrument head, the optical system including at least one distalobjective lens aligned along a viewing axis; a handle portion containingat least one battery, the instrument head being attached to the handleportion; a digital image forming device aligned along the viewing axisand configured to receive an image of a medical target from the opticalsystem; and at least one control button for enabling a first normalviewing mode and a second zoom magnification mode.
 2. The instrument ofclaim 1, further comprising a tip element releasably attached to thedistal insertion portion.
 3. The instrument of claim 2, in which theinstrument is an otoscope configured to examine a body cavity includingan ear canal or a nasal cavity.
 4. The instrument of claim 1, furthercomprising an accelerometer for detecting an orientation of theinstrument.
 5. The instrument of claim 4, in which the accelerometer iscoupled to the digital image forming device, the digital image formingdevice being configured to reverse an image of a medical target by 180degrees when the accelerometer determines that the instrument is beingheld in a reverse orientation by 180 degrees.
 6. The instrument of claim1, wherein the at least one control button is configured to permittoggling between the first normal viewing mode and the second zoommagnification mode.
 7. The instrument of claim 1, in which the zoommagnification mode magnifies a center portion of a default field of viewof the digital image forming device obtained in the first normal viewingmode.
 8. The instrument of claim 7, in which the center portion of thedefault field of view is approximately one half of the diameter of thefield of view.
 9. The instrument of claim 1, further comprising amicrophone configured to input audio information for storage andcommunication with image information of the digital image formingdevice.
 10. The instrument of claim 1, further comprising a displaycoupled to the digital image forming device.
 11. The instrument of claim1, further comprising a focusing mechanism for axially moving at leastone lens of the optical system.
 12. The instrument of claim 1, in whichthe proximal end of the instrument head includes an eyepiece.
 13. Theinstrument of claim 1, in which the digital image forming device isattached to the instrument head.
 14. The instrument of claim 1, in whichthe digital image forming device is disposed within the instrument head.15. The instrument of claim 14, further comprising a focusing mechanismfor axially moving the digital image forming device relative to theoptical system.
 16. The instrument of claim 1, including a communicationchannel for transmitting images obtained by the digital forming deviceto a remote location.
 17. The instrument of claim 16, in which thecommunication channel is wireless.
 18. The instrument of claim 1,further comprising memory for storing images obtained by the digitalimage forming device.